Was considering buying this on blu-ray. Never seen it and need a 3rd movie to pick in a "buy 3" deal and Das Boot Director's Cut (UK version) is an option.

I wouldn't hesitate at all. You do need to take breaks when watching this, it's like 4 hours long, so set aside an entire night to do it, but it's never boring. On the contrary, it's one of those films I can watch over and over and over.